Field of the Invention
The invention relates to an image capturing device, and more particularly, relates to a method for calibrating image deformation of an image capturing device.
Description of Related Art
With development in technology, various smart image capturing devices, such as tablet computers, personal digital assistants and smart phones, have become indispensable tools for people nowadays. Camera lenses equipped in high-end smart image capturing devices provide same or better specifications than those of traditional consumer cameras, and some even provide three-dimensional image capturing features or near-equivalent pixel qualities to those of digital single lens reflex cameras.
Generally, during an autofocusing procedure, an image capturing device may be focused by adjusting positions of lenses through a focusing actuator such as a stepping motor, a voice coil motor (VCM) and so on. Hence, before such image capturing device leaves the factory, a corresponding relation between a focusing distance of a target and a moving step of the focusing actuator may be archived into a conversion table and pre-stored in the image capturing device. Accordingly, when the image capturing device executes the autofocusing procedure on an arbitrary target, the focusing distance of such target may be obtained according to depth information thereof, so that the number of steps that the focusing actuator is required to move may be acquired and the lenses may be adjusted accordingly. However, in practical use, deformation or offset usually occurs on the lenses and the focusing actuator of the image capturing device due to external factors such as drop-offs, bumps, squeezes, changes in temperatures or humidity. The auto-focusing procedure may thus cause errors when the image capturing device captures images.